Hey there jst joined the Skyline club and new to it aswell since i jst bought the car 2 days ago lolz, and got the same problem when i start hittin the bumps on PARAMATTA RD (FullY ShockinG) thought the seller done me over, but had closer look, it was jst like yours getting a lip in the rotor groove, it was the rotor fenders (that shield thingy behind the rotor) it was touchin, jst had to apply good amount of pressure on top and bottom n push em back (sorta bendin it backwards) did the trick.